Improvement in processes of producing salicylic acid



W. E. GRAF.

Process of Producing SalicyHc Acid.

No.l66,86 3.

PatenfedAug.17,1875.

lmimmw W. 5 7

g A; Z2427 'WMQWM: J? ejllrrag @MM UNITED STATES PATENT QFFIGE.

WILHELM EHREN FRIED GRAB, OF NEW YORK, ASSIGNOR TO HIMSELF AND SAMUEL W.GANFIELD, OF PIERMONT, N. Y.

IMPROVEMENT IN PROCESSES OF PRODUCING SAL'ICVLIC ACID.

Specification forming part of Letters Patent No. 166,863, dated August17, 1875 application filed June 22, 1875.

CASE B.

To all whom it may concern:

Be it known that I, WILHELM EHREN- FRIED GRAF, of the city of New York,in the county and State of New York, have invented a new and ImprovedProcess of Producing Salicylic Acid, of which the followingis aspecification:

The drawing represents a side elevation, partly in section, of theapparatus which I prefer to use in carrying my invention into effect.

The object of this invention is to improve boiler G. This still orboiler is charged with caustic soda or other alkali, and with carbolicacid, in the usual proportions employed in the manufacture of salicylicacid, and is placed on an oven or heater, D, whereby its contents areheated to the requisite degree. The carbonic-acid gas entering theheated contents of the still through the pipe a mingles with the same,and thus the salicylate of soda, or other salicylate of alkali, isproduced, which, upon its removal from the still, is boiled in water toremove the superfluous carbolic acid, and finally exposed to the actionof muriatic acid, in which the salicylic acid forms as a whiteprecipitate.

None of the proceedings hereinabove described do I claim to haveinvented but my invention consists in boiling the ingredients in thestill 0 under pressure, and in thereby obtaining a more perfectcommingling of the ingredients, and a consequent greater yield ofsalicylic acid, than when boiling in an open still, and losing in avaporous state many particles of carbolic acid and soda.

Of course the still or boiler should have a means of discharging surplusvapors, and I therefore prefer to provide its neck or discharge-pipe bwith a cock, 0. When this cock is opened, the still or boiler maydischarge into a vessel, E, whence the contents may be poured back intothe still or boiler through a pipe, f, having a cock, g. The still orboiler 0 should also have a safety-valve, d, and a thermometer, h,- butI do not here lay claim to any arrangement of apparatus, as I claim andhere desire to secure by Letters Patent The process herein described ofmanufacturing salicylic acid by conducting carbonic acid from agenerator into a closed still, which contains a mixture of carbolic acidand an alkali, while its contents are heated, substantially asspecified.

GRAF.

Witnesses:

A. V. BRIE-SEN, E. 0. WEBB.

